30 Geologic Studies of the U.S. Atlantic Coastal Plain (Posters)

Friday, 29 March 2019
8:00 AM - 12:00 PM
Carolina Ballroom

INVESTIGATION OF SEDIMENT DYNAMICS WITHIN QUEEN CREEK, VIRGINIA: A COLLABORATIVE PROJECT BETWEEN 2-YR AND 4-YR INSTITUTIONS

Paper number: 30-9
Program: Theme Sessions
Time: 8:00 AM – 12:00 PM

Authors

Abstract

Queen Creek is a moderately sized, semi-diurnal tributary to the York River and Chesapeake Bay, in southeastern Virginia and incises into Miocene and Pliocene estuarine to marine sediments of the Eastover and Yorktown Formations and several Pleistocene alloformations. With a drainage basin area of ~60 km2, the ~10 km long stream collects water from the developed City of Williamsburg and records a variety of human impacts from residential, agricultural, and military activity within the watershed, extending as far back as the Colonial Period of the Early American colonies. Sedimentation within the creek recently led to local shoaling of the navigable channel and filled in a majority of docks within a small private marina. We are studying the sedimentation history of this creek to elucidate evidence of longer-term impacts of climate change along the eastern seaboard of North America and shorter-term impacts of various human activities within the watershed. Three 2 m piston cores were extracted from within the modern channel: near the mouth, approximately mid-length of the creek, and immediately downstream from a major interstate expansion project spanning the creek, near the headwaters. Cores were analyzed for magnetic susceptibility, bulk density, organic matter content, and grain size. The upper and middle sites are primarily silt with 10-15% organic matter with sections having lower organic content and higher concentrations of fine sand. Radiocarbon dating and analysis of 137Cs concentrations were used to determine that the upper core has a basal age of c. 2500 cal yr BP and indicates sedimentation rates of ~0.08-0.22 cm/yr, while the middle site shows higher sedimentation rates with preliminary results showing rates of 0.35 cm/yr over the last 50 years. These differences could reflect historical activities in the middle section of Queen Creek, or may be linked to more complex dynamics related to sedimentation between the upper and lower reaches of the channel.

This project also highlights a novel, grant supported relationship between a 2yr and 4yr institution, during which 2yc faculty and students worked alongside 4yr faculty and students, gaining access to resources and experiences traditionally unattainable at 2yc institutions.

Geological Society of America Abstracts with Programs. Vol. 51, No. 3

doi: 10.1130/abs/2019SE-326822

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